Device and method for positioning in a magnetic field of a magnetic resonance tomography system using magnetic field strength

Patent metadata

Field	Value
Publication number	US-10545201-B2
Application number	US-201815892824-A
Country	US
Kind code	B2
Filing date	Feb 9, 2018
Priority date	Feb 15, 2017
Publication date	Jan 28, 2020
Grant date	Jan 28, 2020

Abstract

The disclosure relates to a positioning device for positioning in a static magnetic field of a magnetic resonance tomography system and a magnetic resonance tomography system. The positioning device may be moved along a first axis in the magnetic field. Herein, the positioning device includes a plurality of magnetic-field-strength sensors arranged at a distance from one another in the direction of the first axis in predetermined positions on the positioning device.

First claim

The invention claimed is:

1. A positioning device for positioning in a static magnetic field of a magnetic resonance tomography system, the positioning device comprising:
a plurality of calibrated magnetic-field-strength sensors arranged at a distance from one another in a direction of a first axis in the magnetic field in predetermined positions on the positioning device,
wherein the positioning device is configured to move along the first axis in the magnetic field, and
wherein the plurality of calibrated magnetic-field-strength sensors is configured to provide an absolute magnetic-field strength.

2. The positioning device of claim 1 , wherein the first axis is substantially aligned parallel to a field direction of the static magnetic field.

3. The positioning device of claim 1 , further comprising:
a position-determining facility configured to identify a predetermined reference position of the positioning device in relation to the magnetic field.

4. A magnetic resonance tomography system comprising:
a positioning device configured to be positioned in a static magnetic field of the magnetic resonance tomography system, wherein the positioning device comprises:
a plurality of calibrated magnetic-field-strength sensors arranged at a distance from one another in a direction of a first axis in the magnetic field in predetermined positions on the positioning device,
wherein the positioning device is configured to move along the first axis in the magnetic field, and
wherein the plurality of calibrated magnetic-field-strength sensors is configured to provide an absolute magnetic-field strength.

5. The magnetic resonance tomography system of claim 4 , wherein the positioning device further comprises a position-determining facility configured to identify a predetermined reference position of the positioning device in relation to the magnetic field,
wherein the position-determining facility comprises an automatically acquirable reference mark and a marking sensor,
wherein the reference mark and the marking sensor are configured to be moved along the first axis in relation to one another by the positioning device, and
wherein the marking sensor is designed to output a reference signal at a predetermined relative position to the reference mark.

6. The magnetic resonance tomography system of claim 4 , further comprising:
a controller; and
a memory,
wherein the controller is configured to move the positioning device along the first axis to receive a signal with a magnetic-field strength from a calibrated magnetic-field-strength sensor of the plurality of calibrated magnetic-field-strength sensors and compare the received signal with a stored magnetic-field strength value.

7. The magnetic resonance tomography system of claim 6 , wherein the memory has stored magnetic-field strength values for different positions of the calibrated magnetic-field-strength sensor along the first axis.

8. The magnetic resonance tomography system of claim 6 , further comprising:
a position-determining device configured to determine a position of the positioning device relative to the magnetic resonance tomography system along the first axis,
wherein the controller is configured to move the positioning device along the first axis into different positions and to acquire measured values of the calibrated magnetic-field-strength sensor at the positions approached and, by the position-determining device, the respective position and store the measured values in the memory.

9. A patient bed comprising:
a positioning device configured to be positioned in a static magnetic field of a magnetic resonance tomography system, wherein the positioning device comprises a plurality of calibrated magnetic-field-strength sensors arranged at a distance from one another in a direction of a first axis in the magnetic field in predetermined positions on the positioning device, wherein the positioning device is configured to move along the first axis in the magnetic field; and
a moving unit by which the patient bed is configured to move along a plurality of axes in relation to the magnetic resonance tomography system,
wherein the positioning device is configured to determine a position, an orientation, or both the position and the orientation of the patient bed relative to the magnetic resonance tomography system and to output a position-deviation signal as a function of the relative position determined and a predetermined setpoint position, and
wherein the plurality of calibrated magnetic-field-strength sensors is configured to provide an absolute magnetic-field strength.

10. The patient bed of claim 9 , wherein the patient bed is configured to control the moving unit as a function of the position-deviation signal such that the patient bed adopts the predetermined setpoint position.

11. A method for calibration of a positioning device of a magnetic resonance tomography system, the method comprising:
determining, by a position-determining device of the magnetic resonance tomography system, a relative position of the positioning device in relation to the magnetic resonance tomography system, wherein the position-determining device includes a plurality of magnetic-field-strength sensors;
acquiring, by a controller of the magnetic resonance tomography system, a measured value of the magnetic-field-strength sensor, wherein the measured value provides an absolute magnetic-field strength; and
storing the measured value and the relative position in a memory of the magnetic resonance tomography system.

12. A method for calibration of claim 11 , wherein the determining, the acquiring, and the storing are repeated for a plurality of different relative positions.

13. A method for calibration of claim 12 , wherein the method for some or all of the plurality of magnetic-field-strength sensors is repeated.

14. The method for calibration of claim 11 , wherein a reference magnetic-field-strength value is stored in the memory and in the determining of the relative position further comprises:
moving the positioning device along a first axis;
acquiring a measured value of the magnetic-field-strength sensor;
comparing the acquired measured value with the stored reference magnetic-field-strength value; and
stopping the positioning device when the acquired measured value matches the stored reference magnetic-field-strength value or repeating the moving, the acquiring, and the comparing when the acquired measured value does not match the stored reference magnetic-field-strength value.

15. A method for positioning a positioning device at a predetermined relative position with a magnetic resonance tomography system, the method comprising:
determining, by a controller of the magnetic resonance tomography system, a calibrated magnetic-field-strength sensor from a plurality of calibrated magnetic-field-strength sensors;
ascertaining, by the controller, a magnetic-field strength assigned to the predetermined relative position as a function of the determined calibrated magnetic-field-strength sensor and the relative positions and magnetic-field strength values stored in a memory of the magnetic resonance tomography system, wherein the magnetic-field-strength values indicate an absolute magnetic-field strength;
moving the positioning device along a first axis;
acquiring a measured value of the determined calibrated magnetic-field-strength sensor;
comparing the acquired measured value with the ascertained magnetic-field strength; and
stopping the positioning device when the acquired measured value matches the ascertained magnetic-field strength or repeating the moving

Assignees

• Hetz Christian
• Petsch Markus
• Pflichtbeil Ronny
• Schmidt Rolf
• Sukkau Johann
• Siemens Healthcare Gmbh

Inventors

• Hetz Christian
• Petsch Markus
• Pflichtbeil Ronny
• Schmidt Rolf
• Sukkau Johann

Classifications

• G01R33/0023

  Electronic aspects, e.g. circuits for stimulation, evaluation, control; Treating the measured signals; calibration (G01R33/0017 takes precedence) · CPC title

• G01R33/543

  Control of the operation of the MR system, e.g. setting of acquisition parameters prior to or during MR data acquisition, dynamic shimming, use of one or more scout images for scan plane prescription (G01R33/546 takes precedence) · CPC title

• G01R33/072

  Constructional adaptation of the sensor to specific applications · CPC title

• G01R33/307 Primary

  specially adapted for moving the sample relative to the MR system, e.g. spinning mechanisms, flow cells or means for positioning the sample inside a spectrometer · CPC title

• A61B5/704

  Tables · CPC title